Progress in ITER project and its superconducting magnet system in Japan

日本におけるITER計画の進捗と超伝導マグネットシステム

奥野 清; 中嶋 秀夫; 高橋 良和; 小泉 徳潔

Okuno, Kiyoshi; Nakajima, Hideo; Takahashi, Yoshikazu; Koizumi, Norikiyo

ITERとは、日本,欧州,米国,ロシア,中国,韓国,インドの7極が参加している国際共同プロジェクトで、環境への負荷が少なく人類の恒久的なエネルギー源の一つとして期待される核融合エネルギーの科学的,技術的な実現可能性の実証を目的に、実験炉を建設・運用するものである。ITERは2018年の運転開始を目指し、欧州をホスト極として南フランスのカダラッシュで既に建設が開始されている。ITERでは、日本には7極の中でも「準ホスト極」として非常に重要な役割が期待されており、特に超伝導コイルでは、これまでの開発実績が広く認められ、NbSn超伝導導体やトロイダル磁場コイルなどの主要部分を分担し、貢献度はITER参加極中で最大となっている。本講演及び論文では、これらITERの現状とITERに利用される日本の先端超伝導技術について発表する。

ITER is a joint international project and its participants are the European Union, Japan, the People's Republic of China, India, the Republic of Korea, the Russian Federation and the USA. The ITER, will be constructed in Europe, at Cadarache in France. ITER will demonstrate high power amplification and extended burn of deuterium-tritium plasmas, in a steady state as an ultimate goal, with the technologies essential to a reactor in an integrated system. Superconducting magnets are one of these technologies, which induce an electrical current and confine and control the reacting plasma. The ITER superconducting magnet systems consist of 18 Toroidal Field (TF) coils, 6 Poloidal Field (PF) coils, a Central Solenoid (CS) coil, Correction Coils, and related structures. Maximum fields are 11.8 T in the TF coil, 13 T in the CS, and below 6 T in the PF coils. The CS and TF coils use NbSn superconductor and PF coils use NbTi conductor. Japanese contribution to the construction of the ITER superconducting magnet system is to procure 25% of TF conductors, about half of TF coil winding packs, all of TF coil structures and all of CS conductors. Total amount of raw stainless steel materials required for the TF coil structures is more than 10,000 tons. The Japanese Domestic Agency, represented by Japan Atomic Energy Agency (JAEA), has performed extensive technology development for the preparation of these procurements. These include (1) trial fabrication of the superconductors at industry level and their performance demonstration, (2) manufacturing studies and full-scale trial fabrication of TF coil including its structures, and (3) establishment of database on the structural materials.